Medical Device And Method To Correct Deformity

ABSTRACT

A system for correcting a spinal deformity includes an implant fixed to one side of a vertebra and a rod extending along an axis of the spine on a second side of the vertebra. An adjustment member, which may include a reel, is coupled to the rod. A force directing member, such as a cable, extends between the rod and the adjustment member. The force directing member is retractable toward and extendible from the adjustment member. A method of correcting spinal deformity includes providing an implant, a rod, an adjustment member coupled to the rod, and a force directing member extending between the rod and the adjustment member. The adjustment member can be retractable toward and extendible from the adjustment member.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/817,750, filed Nov. 20, 2017, which is a continuation ofU.S. patent application Ser. No. 14/628,573, filed Feb. 23, 2015 nowU.S. Pat. No. 9,848,917, which is a continuation of U.S. patentapplication Ser. No. 13/446,950, filed Apr. 13, 2012, which is acontinuation of U.S. patent application Ser. No. 12/134,058, filed Jun.5, 2008, now U.S. Pat. No. 8,162,979, which claims priority to U.S.Provisional Application Ser. No. 60/933,326, filed Jun. 6, 2007. Theabove-referenced applications are expressly incorporated herein byreference in their entireties.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This application generally relates to devices and methods for adjustinganatomical structures. More particularly, this application related todevices and methods for correcting skeletal deformities, such as spinaldeformities.

2. Description of the Related Art

Certain spine conditions, defects, deformities (e.g., scoliosis) as wellas injuries may lead to structural instabilities, nerve or spinal corddamage, pain or other manifestations. Back pain (e.g., pain associatedwith the spinal column or mechanical back pain) may be caused bystructural defects, by injuries or over the course of time from theaging process. For example, back pain is frequently caused by repetitiveand/or high stress loads on or increased motion around certain boney orsoft tissue structures. The natural course of aging leads todegeneration of the disc, loss of disc height, and instability of thespine among other structural manifestations at or around the spine. Withdisc degeneration, the posterior elements of the spine bear increasedloads with disc height loss, and subsequently attempt to compensate withthe formation of osteophytes and thickening of various stabilizingspinal ligaments. The facet joints may develop pain due to arthriticchanges caused by increased loads. Furthermore, osteophytes in theneural foramina and thickening of spinal ligaments can lead to spinalstenosis, or impingement of nerve roots in the spinal canal or neuralforamina. Scoliosis may also create disproportionate loading on variouselements of the spine and may require correction, stabilization orfusion.

Pain caused by abnormal motion of the spine has long been treated byfixation of the motion segment. Spinal fusion is one way of stabilizingthe spine to reduce pain. In general, it is believed that anteriorinterbody or posterior fusion prevents movement between one or morejoints where pain is occurring from irritating motion. Fusion typicallyinvolves removal of the native disc, packing bone graft material intothe resulting intervertebral space, and anterior stabilization, e.g.,with intervertebral fusion cages or posterior stabilization, e.g.,supporting the spinal column with internal fixation devices such as rodsand screws. Internal fixation is typically an adjunct to attainintervertebral fusion. Many types of spine implants are available forperforming spinal fixation, including the Harrington hook and rod,pedicle screws and rods, interbody fusion cages, and sublaminar wires.

Spinal stenosis pain or from impingement of nerve roots in the neuralforamina has been treated by laminectomy and foraminotomy. Thereafter,the posterior spine is sometimes reinforced with rod and screw fixation.More recently, surgeons have attempted to relieve spinal stenosis bydistracting adjacent spinous processes with a wedge implant. Pain due toinstability of the spine has also been treated with dynamicstabilization of the posterior spine, using elastic bands that connectpedicles of adjacent vertebrae.

A number of spinal deformities exist where the spine is abnormallytwisted and or curved. Scoliosis is typically considered an abnormallateral curvature of the vertebral column.

Correction of scoliosis has been attempted a number of ways. Typicallycorrection is followed by fusion. For example, a Harrington rod has beenused where a compressing or distracting rod is attached above and belowa curved arch of the deformity. The spine is stretched longitudinally tostraighten the spine as the rod is lengthened. The spine is then fused.The correction force in this device and in similar devices is adistraction force that may have several drawbacks including possiblespinal cord damage, as well as the high loading on the upper and lowerattachment sites. Nowadays, segmental hook and screw fixation exists forproviding distraction and derotating corrective forces.

A Luque device has been used where the spine is wired to a rod atmultiple fixation points along the rod and pulls the spine to the rod.The spine is pulled to the rod with a wire and the spine is then fused.Anterior procedures also exist in the form of fusion via rod and screwfixation systems and newer technology involving staples across the discspace that purport to correct the deformity without requiring fusion.The corrective force is derotation with or without compression.

SUMMARY OF THE INVENTION

In accordance with one embodiment, a system for correcting a spinaldeformity is described. The system for correcting a spinal deformitycomprises at least one implant configured to be fixed to a first side ofa vertebra. The system further comprises a rod adapted to extendgenerally along an axis parallel to an axis of the spine, on a secondside of the vertebra, and at least one adjustment member coupled to therod. The system further comprises at least one force directing memberadapted to extend between the implant and the adjustment member. Theforce directing member is retractable toward and extendible from theadjustment member. In one aspect of the embodiment, the system comprisesa plurality of implants and a plurality of force directing members. Insuch an aspect, the system can comprise a plurality of adjustmentmembers, and each of the force directing members can extend between oneof the implants and one of the adjustment members. In one aspect of theembodiment, the force directing member is a cable. In a further aspect,the adjustment member comprises a reel. In such an aspect, the systemfor correcting a spinal deformity may comprise a housing at leastpartially surrounding the reel. In the same aspect, the reel may berotatable on an axis normal to the axis of the rod. Alternatively, thereel may be rotatable on an axis generally in line with the axis of therod. Further in the same aspect, the system may comprise at least onegear configured to turn the reel. In another aspect of the embodiment,the system comprises an implantable motor configured to drive the atleast one adjustment member. In such an aspect, the motor can comprise astepper motor. Additionally, the system can comprise an implantablepower source configured to supply power to the motor. In another aspectof the embodiment, the implants each comprise a first portion configuredfor fixation to a pedicle on the first side of a vertebra and a secondportion configured to extend to the second side of the vertebra when thefirst portion is fixed to the pedicle. In such an aspect, the firstportion may be a pedicle screw. In the same aspect, the second portionmay be configured to pass through a spinous process of the vertebra. Thesystem may further comprise a load-spreading member configured to spreadload applied by the force directing member to the spinous process.

In accordance with another embodiment, a system for correcting a spinaldeformity comprises means for establishing a desired orientation ofvertebrae, means for applying force to an individual vertebra, means fordirecting force to the force applying means, and means for retractingthe force directing means toward the orientation establishing means. Themeans for directing force extends between the force applying means andthe orientation establishing means. In one aspect of the embodiment, thesystem further comprises means for extending the force directing meansaway from the orientation establishing means.

In accordance with yet another embodiment, a system for correcting aspinal deformity comprises an elongate rod and a plurality of adjustmentmembers coupled to the rod and spaced apart along the rod. The systemfurther comprises a plurality of flexible force-directing membersattached to the adjustment member and adapted to be drawn toward the rodby the adjustment member. The system further comprises a plurality ofimplants. The implants are each configured to connect to a vertebra of aspine and to be a force directing member, allowing a plurality ofvertebrae to each be drawn by a said force directing member and a saidadjustment member toward the rod.

In accordance with a further embodiment, a method of correcting a spinaldeformity is described. The method comprises affixing an implant to afirst side of a vertebra and positioning a rod on a second side of thevertebra so that the rod extends generally parallel to an axis of thespine. The method further comprises providing at least one adjustmentmember positioned along the rod and positioning at least one forcedirecting member so that it extends between the adjustment member andthe implant. The method further comprises applying a force to the atleast one force directing member with the adjustment member, therebymoving the vertebra toward the rod. In one aspect of the embodiment, theforce is applied percutaneously. In another aspect, the force is appliednon-invasively. In such an aspect, the force can be applied using HFenergy. In such an aspect, the force can be applied using an implantedpower source. In such an aspect, the force can be applied by animplanted motor. In one aspect of the embodiment, the method comprisesaffixing a plurality of the implants to the first side of a plurality ofvertebrae and providing a plurality of the adjustment members positionedalong the rod. In such an aspect, the method further comprisespositioning a plurality of the force directing members betweenadjustment members and implants, and then applying a force to each ofthe plurality of force directing members. In such an aspect, a differentforce may be applied to each force directing member. In another aspect,the force directing member is a wire. In yet another aspect, the forcedirecting member is a cable. In a further aspect, the adjustment membercomprises a reel. In such an aspect, the method can further compriseproviding a housing at least partially surrounding the reel. In the sameaspect, the reel can be rotatable on an axis normal to the axis of therod. Alternatively, the reel may be rotatable on an axis generally inline with the axis of the rod. Further in such an aspect, the method maycomprise at least one gear configured to turn the reel. In anotheraspect of the embodiment, the implant comprises a first portionconfigured for fixation to a pedicle on the first side of a vertebra anda second portion configured to extend to the second side of the vertebrawhen the first portion is fixed to the pedicle. In such an aspect, thefirst portion may be a pedicle screw. In the same aspect, the secondportion may be configured to pass through a spinous process of thevertebra. The method may further comprise a load-spreading memberconfigured to spread load applied by the force directing member to thespinous process. In a further aspect, the implant is affixed to multiplelocations on the vertebra such that applying the force to the forcedirecting member with the adjustment member both moves the vertebratoward the rod and derotates the vertebra.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features of the invention will now bedescribed with reference to the drawings of various embodiments whichare intended to illustrate but not to limit the invention. The drawingscontain the following figures:

FIG. 1 is a schematic view of a spine deformity correction system inaccordance with an embodiment.

FIG. 2 is an enlarged view of a portion of FIG. 1 showing a fixationdevice in accordance with the illustrated embodiment.

FIG. 3 is a perspective view of a fixation device according to anembodiment.

FIG. 4 is an exploded view of the fixation device shown in FIG. 3.

FIG. 5 is a perspective view of the transverse member of the fixationdevice shown in FIG. 3.

FIG. 6 is a top plan view of a fixation device according to anembodiment, shown implanted in a vertebra.

FIGS. 7A through 7C show plan views of various load-spreading membersthat can be used with embodiments of the invention.

FIG. 8 is an enlarged view of a portion of FIG. 1 showing an adjustmentmechanism in accordance with the illustrated embodiment.

FIGS. 9 through 13 show schematic views of adjustment mechanismsaccording to various embodiments.

FIG. 14 is a schematic view of a spine deformity correction system inaccordance with a further embodiment.

FIG. 15 is an enlarged view of a portion of FIG. 14 showing anadjustment mechanism in accordance with the illustrated embodiment.

FIG. 16 is a process diagram illustrating a method of correcting aspinal deformity, according to a further embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following description and the accompanying figures, which describeand show certain preferred embodiments, are intended to demonstrateseveral possible configurations that systems for adjusting anatomicalstructures can take to include various aspects and features of theinvention. The illustrated embodiments are shown correcting a scolioticcurvature of a spine. The illustration of embodiments in this context isnot intended to limit the disclosed aspects and features of theinvention to the specified embodiments or to usage only in correctingscoliosis. Those of skill in the art will recognize that the disclosedaspects and features of the invention are not limited to anyspecifically disclosed embodiment, and systems which include one or moreof the inventive aspects and features herein described can be designedfor use in a variety of applications.

As used herein, the term “vertical” refers to a direction generally inline with, or generally parallel to, a sagittal plane of the body (e.g.,generally parallel to the axis of a straightened spine in a standingpatient). The terms “transverse” and “horizontal” refer to a directiongenerally in line with, or generally parallel to, a transverse plane ofthe body (or a transverse plane of a vertebral body), and normal to asagittal plane of the body (e.g., running from side to side across thespine of a standing patient).

The preferred embodiments of the present invention advantageouslyprovide improved systems and methods for adjusting or correcting ananatomical structure, such as an abnormally curved spine, in a patient.According to one embodiment, the system includes a rod which can bedisposed along a vertical axis to one side of a patient's spine. Thesystem also includes one or more fixation devices or implants that canbe disposed on the other side of the patient's spine, each of which canbe inserted into, or otherwise attached to, one or more vertebrae. Aconnector extends between each implant and the rod. Coupled to the rodis at least one adjustment mechanism which is coupled to the connector.Activation of the adjustment mechanism adjusts the length of theconnector, allowing adjustment of the forces applied to an individualvertebra through the connector and its associated implant. Someembodiments of the invention thus allow for reversibly adjustable forcesto be applied to individual structures, such as individual vertebrae,allowing tensioning and loosening as appropriate. Embodiments of thesystem can be implanted surgically and then tightened (or loosened) overan extended period of time if desired, with minimally invasive ornoninvasive procedures to provide gradual adjustment. Embodiments alsoprovide a system for correcting a deformity of the spine which can beused with or without fusion.

With reference now to FIG. 1, a system 100 generally includes astabilizing rod 102, one or more implants 104, one or more adjustmentmechanisms 106, and one or more connectors 108. The rod 102 extendsgenerally vertically and is secured to individual vertebrae at locationsabove and below the curvature to be corrected. The illustrated rod 102is attached, according to known methods, to transverse processes on theleft side of the spine. Among other functions, the rod serves toestablish a desired orientation of the spine. The rod 102 can have anadjustable length, such that its length can adapt to the changing lengthof the spine as its curvature is straightened. The rod can be atelescoping rod, or the rod can comprise rotatable threaded portionsthat may be actuated to change overall length of the rod. In addition orin the alternative, the rod 102 can be movable with respect to either orboth of the attachment points above and below the curvature of thespine, so as to allow the system 100 to adapt to the lengthening of thespine as the affected vertebrae are translated toward the rod 102. Sucha configuration can advantageously prevent buckling in the rod 102and/or the spinal column as the curvature of the spine is corrected.

The implants 104 are shown fixed to individual vertebrae within thecurved portion of the spine, on the opposite side of the spine from therod 102. The implants 104 include transverse portions 110 which extendacross the spine, toward the rod 102. As better illustrated in FIG. 2,the transverse portions 110 can pass through the spinous processes ofindividual vertebrae. Each of the transverse portions 110 is coupled toone of the connectors 108. The connectors 108 extend transversely fromthe transverse portions 110 of the implants 104 toward the rod 102, andare coupled to the rod 102 via the adjustment mechanisms 106. Theconnectors 108 are preferably flexible so that they can be used withadjustment mechanisms 106 of a spooling or winding type. Suitableflexible connectors 108 include monofilament polymer materials,multifilament polymer materials (such as or similar to string or rope),multifilament carbon or ceramic fibers, wire, and multi-stranded cable.Stainless steel or titanium wire or rope are some examples of suitablematerials. Of course, a wide variety of materials can be used to makethe connectors 108. In an embodiment, those materials are preferablybiocompatible; indeed, the entire system is preferably made ofbiocompatible materials.

FIGS. 3 and 4 illustrate in detail an implant 200 configured inaccordance with an embodiment. The implant 200 includes a fixationportion 202 which is configured to be fixed to a portion of a vertebra,such as a pedicle. The fixation portion 202 can comprise any suitablestructure capable of engaging a portion of a vertebra, such as, forexample, the illustrated pedicle screw. The implant 200 also includes atransverse portion 204 coupled to the top end 206 of the fixationportion 202. The transverse portion 204 is disposed generallyperpendicularly to the fixation portion 202. The fixation portion 202includes at its top end 206 a slot 208 configured to receive a first end210 of the transverse portion 204. The slot 208 is sized to receive aset screw 212 which, when engaged in the slot 208 on top of the firstend 210 of the transverse portion 204, serves to secure the position ofthe transverse portion 204 relative to the fixation portion 202. Inaddition to or instead of the set screw 212, an external nut 218 can beused to provide additional securement of the transverse portion 204relative to the fixation portion 202. Of course, as will be understoodby one of skill in the art, any suitable coupling can be used to jointhe fixation portion 202 and the transverse portion 204. Further,depending on the particular application, the implant can also have aunitary construction.

A connector 214 extends from a second end 216 of the transverse portion204 by an amount sufficient to connect to an adjustment mechanismcoupled to a rod, as described herein. The connector 214 can be attachedto the first end 210 of the transverse portion 204, extending along thelength of and past the second end 216 of the transverse portion 204.Alternatively, the connector 214 can be attached at any other locationalong the length of the transverse portion 204. The connector 214 mayadvantageously comprise, for example, a cable or wire, or anothermaterial as set forth above, and can be fixed to the transverse portion204 in any suitable manner, such as by welding or screw fixation. FIG. 5illustrates the transverse portion 204 in further detail. As shown inthe figure, the transverse portion 204 can have a wider, roughlydisk-shaped first end 210 so as to engage the receiving slot 208 in thefixation portion 202. Of course, the first end 210 of the transverseportion 204 and the top end 206 of the fixation portion 202 can have anyother suitable cooperating configuration so as to guide and engage oneanother in an appropriate orientation. The transverse portion 204 canalso have a hollow construction through which the connector 214 canextend.

With reference now to FIG. 6, an implant 300 in accordance with anembodiment is shown fixed to a single vertebra. The implant 300 includesa pedicle screw 302 which is fixed to one side of the illustratedvertebra. A transverse member 304 is advantageously coupled to the headof the pedicle screw 302 and extends through the spinous process of theillustrated vertebra. A load-spreading member 306 can be provided whichencircles, or partially encircles the transverse member 304 at the pointof contact between the spinous process and the transverse member 304,contralateral to the adjustment mechanism and rod (not shown in FIG. 6).

FIGS. 7A through 7C illustrate various configurations of load-spreadingelements according to various embodiments. Element 402 has an annularconfiguration configured to spread loads evenly about the point ofcontact with the spinous process. Element 404 includes two wingsextending from a ring configured to encircle the transverse member.Element 406 includes tentacles extending from a ring. Configurationssuch as these can also be used to distribute loads to the lamina, inaddition to spreading loads across a larger surface area of the spinousprocess. Of course, a load-spreading element can have any otherconfiguration suitable for reducing the concentration of force appliedto the spinous process by a transverse member extending therethrough,distributing the forces to other portions of the vertebra (for example,to the lamina), and/or for anchoring the transverse member to thespinous process. In addition, the side of the load-spreading elementsthat contact bone can include such features as barbs, fins, pins, orother similar structure to achieve secure attachment of the extensionsto the vertebral bone.

Although the illustrated embodiments generally include implants havingtransverse members which extend through the spinous process of avertebra, and thus show examples of implants which are fixed at multiplelocations on an individual vertebra, embodiments of the invention alsoinclude implants which are fixed to only a single location on anindividual vertebra. For example, an implant according to an embodimentcan include a transverse member configured to extend between spinousprocesses of adjacent vertebra. In such an embodiment, the transversemember can optionally be anchored to one or both of the adjacent spinousprocesses via a cable, tether, clasp, clamp, screw, hinge, or othersuitable means. In addition, although the illustrated embodimentsgenerally show each implant fixed to a single vertebra, embodiments canalso include one or more implants configured to be fixed to multiplevertebrae. Additional examples of implants, as well as rods, which maybe used with embodiments of the invention are set forth in copendingU.S. application Ser. No. 11/196,952, the disclosure of which is herebyincorporated in its entirety. One advantage of multiple-point fixationis the ability to provide not only translational force to the vertebrathrough the implant, but also rotational force. The amount of rotationalforce will depend in part on the distance between the axis of thevertebra and the point of attachment of the connector 108 to the implant104. This disclosure contemplates selecting or moving that point ofattachment to achieve any desired rotational force, as well as a desiredtranslational force.

With reference now to FIG. 8 a particular adjustment mechanism 106 shownin FIG. 1 is illustrated in further detail. The adjustment mechanism 106may advantageously include a reel 502, a circumferential gear 504surrounding the reel 502, and a vertical gear 506 in contact with thecircumferential gear 504. The connector 108 is preferably attached to orengaged by the reel 502. Actuation of the vertical gear 506 via screwhead 508 turns the circumferential gear 504, which turns the reel 502,thus winding (or unwinding, depending on the direction in which the reel502 is turned) the connector 108 about the reel 502. Tightening of thereel 502 draws the connector 108 in toward the adjustment mechanism 106,thus pulling the associated implant 104 (not shown in FIG. 8) toward theadjustment mechanism. The reel 502 and the gears 504, 506 are housed ina clamp 510. The adjustment mechanism 106 can be immovably fixed to therod 102 or can be movable with respect to the rod 102. A movableadjustment mechanism 106 provides advantages, for example, as the spinestraightens and thus lengthens, so that the adjustment mechanisms 106can be moved to accommodate the relative movement of the spine incomparison to the rod 102. A movable adjustment mechanism 106 also tendsto move to the point directly across from the implant 104, which is theposition creating the least amount of tension in the connector 108 andwhich is also the ideal position for correction.

An adjustment mechanism can be configured in any manner suitable forretracting and letting out a connector. FIGS. 9 through 13 show examplesof adjustment mechanisms according to further embodiments. FIG. 9 showsan adjustment mechanism 520 comprising only a single reel or gear 522,around which a connector 524 is wound. The gear 522 is disposed along onan axis normal to the axis of the rod 526. The gear 522 can be directlyactuated to tension or loosen the connector 524. FIG. 10 shows anadjustment mechanism 530 according to a further embodiment. Themechanism 530 includes a spring 532 configured to actuate a verticalgear 534. The vertical gear 534 contacts a circumferential gear 535 on areel 536 around which a connector 538 is wound. In such an embodiment,the spring 532 can exert gradual forces on the connector 538 (and thus,on an implant to which the connector 538 is attached) without the needfor puncturing the patient's skin. FIG. 11 shows an adjustment mechanism540 according to another embodiment. The mechanism 540 includes animplantable power supply 542 configured to actuate a motor 544. Themotor 544 drives a gear 545 on a reel 546 around which a connector 548is wound. In such an embodiment, the motor 544 can be configured toexert gradual forces on the connector 548 (and thus, on an implant towhich the connector 548 is attached) without the need for puncturing thepatient's skin after the initial implantation of the system. Forexample, the motor 544 can be configured to draw in the connector 548 ata predetermined rate (e.g., 3 mm per day). In some embodiments, themotor 544 can be a stepper motor configured to draw in the connector 548in incremental amounts over time. In other embodiments, the motor 544can be configured to exert a predetermined amount of tension on theconnector 548. Such embodiments can include one or more sensors,controllers, and related circuitry configured to measure the amount oftension on the connector 548 and adjust the tension applied by the motor544 accordingly. Such embodiments can be configured to time-average theamount of tension on the connector 548 to allow for variation in tensioncaused by movement of the patient. In addition, such embodiments can beconfigured to maintain varying levels of tension on the connector 548 atdifferent periods throughout the day, for example maintaining a lowerlevel of tension during waking hours and a higher level of tensionduring sleeping hours. Further, in embodiments comprising multipleadjustment mechanisms configured to apply tension to multiple differentvertebrae through multiple connectors, each adjustment mechanism can beconfigured to maintain a different level of tension on its associatedconnector, depending on the needs of the particular application. FIG. 12shows an adjustment mechanism 550 according to a still furtherembodiment. The mechanism 550 is coupled to a rod 551, and includes afirst gear 552 configured to turn a second gear 554. The second gear 554contacts a reel 556, to which a connector 558 is attached. Turning ofthe second gear 554 causes the reel 556 to rotate, thereby pulling in(or letting out) the connector 558 toward (or from) the rod 551. Thefirst gear 552 is driven by an electric motor 559, which is configuredfor remote actuation by an external HF transmission coil 560. Such aconfiguration allows for post-implantation adjustment of the connector558 without puncturing the patient's skin. Any suitable external energysource can be used in an embodiment configured for remote actuation,such as, for example, RF energy, HF energy, or magnetic energy. FIG. 13illustrates an adjustment mechanism 570, according to a still furtherembodiment, coupled to a rod 571. The mechanism 570 includes a reel 572which is actuated by first and second gears 574, 576. The reel 572 isattached to a first connector 578, which extends generally transverselyto an implant on the other side of the spine. Also connected to the reel572 is a second connector 580, which extends generally parallel to therod 571. The second connector 580 is connected to a second adjustmentmechanism (not shown) and configured so that tightening of the mechanism570 results in tightening of the second adjustment mechanism as well. Ofcourse, additional adjustment mechanisms can be coupled to such a systemso that a multiple-implant system can be adjusted using a singleadjustment point.

In the various illustrated embodiments, the adjustment mechanism 106 isshown to be situated along the rod so that the connector 108 extendsgenerally orthogonal to the rod toward the vertebra on which the implant104 is located. Although this is a preferred embodiment, it is alsocontemplated that the adjustment mechanism 106 can be located along therod 102 so that the angle between the axis of the rod 102 and theconnector 108 is other than 90 degrees, e.g., 45 degrees, 60 degrees, 75degrees, or other non-right-angles. Alternatively, instead of locatingthe adjustment mechanism(s) 106 along the rod 102 adjacent to (oropposite) the vertebra to be moved, they could be located more remotely,e.g., at an end of the rod 102. In that configuration, the connectorcould still extend from the implant 104 to the rod 102 at a desiredangle, e.g., generally orthogonal to the rod 102, but could then changedirection (e.g., by passing over a pulley or through a hole in the rod,not shown) and then extend parallel to or coaxial with the rod,alongside the rod or inside the rod, to the adjustment mechanism(s) 106.

With reference now to FIG. 14, a system 600 according to anotherembodiment is illustrated. The system 600 includes a stabilizing rod602, one or more implants 604, one or more adjustment mechanisms 606,and one or more connectors 608. The implants 604 are shown attached toalternate vertebrae. Depending on the particular needs of theapplication, implants 604 can be fixed to all the vertebrae in a curvedportion of a spine, or only certain selected vertebrae. FIG. 15 shows anenlarged view of one of the adjustment mechanisms 606. The adjustmentmechanism 606 includes a housing 610 which surrounds a gear/reelmechanism (not visible in FIG. 15) as described herein. The housing 610includes an opening 612 configured to expose a screw head 614 configuredto actuate the gear/reel mechanism. Such a configuration allows foractuation of the gear/reel mechanism 606 while separating the gear/reelmechanism and surrounding body tissues.

Embodiments also include methods of correcting a spinal deformity. Notethat the following method description relates to some of thecontemplated surgical methods, but it should not be implied that all ofthe recited method steps are mandatory or that they must be performed inthe identical manner specified. Instead, this disclosure is exemplary innature. In some embodiments, individual vertebrae are targeted based ona pre-operative plan for correcting an abnormal curvature a patient'sspine (such as a scoliotic curvature of a patient's spine).Pre-operative planning can involve review of x-rays or CT scans, as wellas physical examination of the patient. Once the targeted vertebrae areidentified, implants are surgically fixed to each of the targetedvertebrae. Fixing each implant can involve fixing a first portion of theimplant into a pedicle of a vertebra on one side of the patient's spine,inserting a second portion of the implant through a spinous process ofthe same or different vertebra, and coupling the first and secondportions together. A vertically extending rod is surgically fixed to theother side of the patient's spine so as to establish a desiredorientation of the targeted vertebrae. Adjustment mechanisms of the samenumber as the implants (that is, the same number as the targetedvertebrae) are movably or immovably fixed to the rod. Connectors arepositioned between each adjustment member and its corresponding implant.The adjustment mechanisms are then actuated to pull the connectors (andthus the targeted vertebrae) toward the rod. The adjustment mechanismsallow for both tightening and loosening of the connectors and, thus, theapplication of force is reversible. The adjustment mechanisms can betightened or loosened as deemed appropriate by the practitioner and thenlocked with a locking mechanism such as a set screw. In embodimentshaving implants coupled to multiple points on each vertebra, applyingtension to the connectors also exerts rotational forces on the targetedvertebrae, thus derotating the spine as the vertebrae are pulled towardthe rod.

Once the initial adjustments are made to the adjustment mechanisms, thesurgical site is closed using standard surgical procedures. The patientis then examined periodically (for example, every 3 to 6 months) andadditional adjustments are made when appropriate. Depending on theconfiguration of the adjustment mechanisms, post-implantation adjustmentcan be made via a percutaneous puncture allowing the passing of a driverto actuate each adjustment mechanism. In embodiments includingadjustment mechanisms configured for remote actuation, adjustments canbe made without the need for puncturing the patient's skin. Adjustmentscan be different at each level or adjustment mechanism, depending on theparticular anatomy to be adjusted, and different forces or force vectorscan be applied to different vertebrae or sections of the spine. Both thecurvature and the mal-rotation of the scoliotic spine can thus becorrected over multiple serial adjustments of the adjustment mechanisms.If desired, the system may be explanted after the deformity of the spineis eliminated or reduced to a clinically acceptable position.

A method of correcting a spinal deformity is illustrated in FIG. 16. Atstep 702, an implant is affixed to a first side of a vertebra. At step704, a rod is positioned on a second side of the vertebra so that therod extends between the adjustment member and the implant. At step 706,an adjustment member is provided which is coupled to the rod. At step708, a force directing member is positioned so that it extends betweenthe adjustment member and the implant. At step 710, a force is appliedto the force directing member with the adjustment member, thereby movingthe vertebra toward the rod.

Embodiments of the invention can be used with or without fusion ofvertebrae. For example, according to embodiments, some vertebrae of thespine may be fused according to known procedures using screws, hooksand/or rod systems following initial or subsequent adjustments or afterexplantation. Alternatively, some or all vertebrae may be leftnon-fused.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In particular, while the present system has been described inthe context of particularly preferred embodiments, the skilled artisanwill appreciate, in view of the present disclosure, that certainadvantages, features and aspects of the system may be realized in avariety of other applications. For example, while particularly useful inthe illustrated scoliosis-correcting application, the skilled artisancan readily adopt the principles and advantages described herein to avariety of other applications, including and without limitation,ameliorating or correcting other spinal conditions such as kyphosis,spondylolisthesis, laxity of spinal motion segments, and other disordersof alignment or loading of the spine.

In addition, as will be understood by one of skill in the art, one ormore adjustment mechanisms according to embodiments can be used toadjust tension on anatomical structures other than spinal structures.For example, embodiments of the invention can be configured and used toadjust the tension, laxity, or distance between an anchor structure andan anatomical structure. Examples of such embodiments include providingan adjustable ligament between the femur and tibia of the leg, forexample to correct a torn cruciate ligament; providing an adjustablesling between the pelvis or pubis and the bladder or urethra for thetreatment of urinary incontinence; providing an adjustable attachmentbetween a bone (such as the pelvis) and the uterus for the treatment ofuterine prolapse; providing an adjustable attachment between themandible or hyoid bone and the tongue or other upper airway structurefor the treatment of snoring or obstructive sleep apnea; and providingan adjustable lifting mechanism between a cranial bone and soft tissueof the face to enable an adjustable face lift or eye lift.

Additionally, it is contemplated that various aspects and features ofthe invention described can be practiced separately, combined together,or substituted for one another, and that a variety of combination andsubcombinations of the features and aspects can be made and still fallwithin the scope of the invention. Thus, it is intended that the scopeof the present invention herein disclosed should not be limited by theparticular disclosed embodiments described above.

What is claimed is:
 1. A system for correcting a spinal deformity, thesystem comprising: at least one implant configured to be fixed to afirst side of a vertebra; a rod adapted to extend generally along anaxis parallel to an axis of the spine and on a second side of thevertebra; at least one adjustment member coupled to the rod; and atleast one force directing member adapted to extend between the at leastone implant and the adjustment member, the at least one force directingmember being retractable toward and extendible from the adjustmentmember.